Self-adjusting wrench



J. W; SAFFOLD.

SELF ADJUSTING WRENCH.

APPLICATION FILED NOV. soqsn 1,363,274. Patented Dec. 28,1920.

2 Shins-SHEET J. W. SAFFOLD.

SELF ADJUSTING WRENCH.

APPLICATION FILED NOV. 30, 1912.

1 3 3 274 Patented Dec. 28, 1920.

2 SHEETS-SHEET 2- II il l lLllli F l lilll I/VJ/ENTOR W114 ITE STATESPATENT OFFICE.

JAMES WEBB SAFFOLID, 0F CLEVELAND, OHIO; ASSIGNOR, BY MESNE ASSIGNMENTS,T0 VICTOR MANUFACTURING COMPANY, OF DAYTON, OHIO.

SELF-ADJUSTING WRENCH.

Specification of Letters Patent. Patented Dec. 28, 1920.

Application filed November 30, 1917. Serial No. 204,498.

To all whom it may concern:

Be it known that I, JAMES l/VEBB SArroLD, a citizen of the UnitedStates, residing at Cleveland, in the county of ()uyahoga and State ofOhio, have invented certain new and useful Improvements inSelf-Adjusting Wrenches, of which the following is a speci fication.

My invention relates to improvements in self-adj usting wrenches, andhas for its object the provision of a simple, strong and compact Wrenchfor standard hexagonal nuts, bolt-heads, and the like, within the limitsof its adjustable capacity. This wrench is adapted to be used withoutincurring the damage or mutilation commonly experienced with many typesof wrenches, by reason of the fact that the angles or corners of thenuts become worn or bur-red, either through biting or slippage of thewrench aws.

In the patent to Meredith, No. 651,574, June 12, 1900, there is shown atype of wrench which provides an inclosing jaw member adapted toaccommodate hexagonal nuts, and an eccentric circular cam-part designedto grip nuts of various sizes within the jaw. However, I havediscovered, after considerable experiment, that in order to meet actualrequirements, a wrench of this type demands peculiar design andpositloning of the cam-part, to prevent slippage of the nut within thejaw, when it is set up tightly upon its bolt. In a wrench of this type atrue circular cam Wlll not meet the requirements, because of its s1zeand slippage. The cam-part must be compact, and its face a curvedeveloped in accordance with the principles I shall explain.

Unless said cam-part is properly proportioned to engage the outer planeface of the nut at a point either equidistant from the angular facesengaged with the aw member or within or back of a bisecting plane, theforcible tightening of the nut to set it up completely, will cause thecam-part to slip upon the nut, ultimately wear its corners or angles,and defeat any adequate tlghtening of said nut. Accordingly, I havearranged properly to position and design the same face, so that itinvariably will engage a nut of suitable size, and permit it to betightened.

My improvenents may be best explained by making reference to theaccompanying drawings, Where1n:--

Figure 1 IS a view of the jaw member and a portion of the combinedhandle and cam- [wrench as equipped with two sizes of jaw members.

F ig. 3 is a side view thereof, and

Fig. 4 is a side view of the jaw member on a larger scale.

Throughout the figures of the drawings, I have employed the samecharacter of reference to indicate similar parts.

The wrench of my invention comprises but two parts; the inclosing jawmember suitably shaped to receive various sizes of hexagonal nuts, and ahandle pivoted thereto with its integral cam-part adapted to grip thenuts within the jaw as the handle is actuated. Referring to Fig. 1, ajaw member j, shaped in its lower portion to accoming sides forming anangle of as deve loped, or angles of 120 with the transverse portion 7"connecting said sides. A handle it is shown both in engaging oroperative position, and in disengaging position (by dotted lines) ofwhich the extension is broken away. A pivot p unites the handle withsaid jaw member, while an eccentrically positioned cam-part 7c is formedintemodate hexagonal nuts, 71. 6. with conver grally with the handle. Astop or abutment s is provided opposite said cam.

\Vithin the jaw I have shown some seven difi'erent outlines of standardnuts in the respective positions which they would occupy or assume inuse. Themedian line m-mt bisects said jaw member and nuts,

and is supplied for the purpose of explain-.

ing the manner in which the developed curve of the cam-face is isdetermined.

The pivot 10 is eccentrically positioned I and is weakened thereby in acorresponding ratchet wrench. Thus the maximum arc is ascertained toconform to a minimum depth of milling, and this arc is subdivided tocorrespond with the number of nuts to be accommodated in a givenjaw-member. Necessarily, the opening in the jaw-member must besufliciently large to permit the backward movement thereof, upon thelargest size of nut.

In preparing the pattern for the handle,

stop and cam, an outline of the jaw member j is first drawn. The line mmis then drawn along the axis of the figure of the jaw member. The pointswhere the line would be intersected by the rearward sides of therespective nutsplaced within the jaw member are then indicated bydrawing the lines a to g. A pattern of the handle and stop is thenprepared from celluloid or other transparent material; a pattern blankis pivoted on the figure of the jaw member at the point p. The patternblank is then swung on the pivot p until some point within an area ofthe forward end thereof reaches the intersection of the lines a and mm,and this point is indicated on the pattern blank. The

pattern blank is then swung until a point in said forward end thereofcoincides with the intersection of the lines I) and m-m, and this pointis indicated upon the pattern blank. This operation is repeated untilthere is indicated upon said forward end of the pattern blank, thepoints which coincide with the intersections of the lines 0, (Z, 6, f,and g and the line m-m. The pattern blank is then removed from thefigure and the points. indicated thereon connected by a curved line andthe forward edge of the pattern blank is then cut off along said line. Ahandle made from the pattern blank thus prepared will be provided with acam having its face. so curved that its toe is located farther beyondits heel with respect to a line perpendicular to the longitudinal axisof the handle and intersecting the center of the pivot 29 thereof andsaid face of the cam having nut engaging points a to g which will engagethe rearward sides of the nuts at points in the axis of the jaw member,that is, in line with the axes of the nuts which coincide with the axisof the jaw member.

The wrench of Figs. 2 and 3 comprises a common handle-member h with twoterminal jaw'members j shaped to accommodate successive sizes ofhexagonal nuts. The cam faces thereof, are plotted or developed in thesamemanner as I have described with re- 'spect, to the diagram of Fig.1; it being necessary in every". case to" determine "the developed curvewith great accuracy, so that the successive positions or points ofengagement shall be at or upon the pivotal side of a median bisectingplane, but preferably very closely adjacent to said plane. The stops orabutments s serve to turn the jawmembers'reversely upon the nut, as thecampart is withdrawn within the diagonally milled portions of therespective jaw-members. These and the handle are suitably hardened.

The pivots preferably are formed of a tough nickle-steel, suitably upsetin counter-sunk openings provided in the milled portions of eachjaw-member, as shown by dotted lines in the enlarged side elevation,Fig. 4:. j

'1 am not aware of available mathematical formulas for determining theshape of the cam, and preferably developits composite curve throughsuccessive and substantially equal sectors, corresponding in number tothe different sizes of nuts which are to be ]accommodated in eachparticular jaw-mem- Having now' described a wrench embodying myinvention, and more particularly, the manner of arriving at the properlyshaped cam face therefor, I claim asnew, and desire to secure by LettersPatent, the following 1. A self-adjusting wrench comprising a jaw memberhaving sides conforming to hexagonal nuts, a handle pivoted. adjacentits forward end to the rear side of said jaw member at one side of themedian line thereof, and a cam carried by the forward end of the handleand having its face so curved that its toe is located forwardly beyondits heel, such face being adapted to positively engage nuts of varioussizes at points in the median line of the jaw" member.

2. A self-adjusting wrench comprising a jaw member having sidesconforming to hexagonal nuts, a handle pivoted adjacent its forward endto the rear side of said jaw member at one side of tlka median linethere of, and a cam carried by the forward end of the handle having itsface so curved that its toe is locatedv forwardly beyond its heel, suchface being adapted to positively engage nuts of various sizes at theirrearward faces and centrally thereof and at points in the median line ofthe jaw member.

3. A self-adjusting wrench comprising a jaw member having sidesconforming to hexagonal nuts and its rear portion provided with a slot,a handle pivoted adjacent its forward end to the rear portion ofthe jawmember within the slot and at one side of the median line of said jawmember, a cam carried by the forward end of the handle having its faceso curved that its toe is lo cated forwardly beyond its heel, said faceadapted to positively engage nuts of various sizes at points in themedian line of the jaw member, and a stop on the handle adapted toengage the wall of said slot at one position of said handle.

4. A self-adjusting wrench comprising an inclosed jaw member having anut receiving space and the sides thereof conforming to hexagonal nuts,the rear portion of said jaw member having a slot communicating with thenut receiving space and forming a shoulder, a handle pivoted adjacentits forward end to the rear portion of the jaw member within the slotand at one side of the median line of said jaw member, a cam carried bythe forward end of the handle having its face so curved that its toe islocated forwardly beyond its heel, said face adapted to, positivelyengage nuts of various slzes, at points in the median line of the jamemher, and a stop on the forward en of the handle adapted to engage theshoulder at one position of the handle.

In testimony whereof I do now affix my signature in the resence of twowitnesses. J ES WEBB SAFF OLD. Witnesses:

JOHN F. DELL ALBERT LYNN LAWRENCE.

